[RFC v2 2/6] Add the libnative library

[Yeqi Fu]

Signed-off-by: Yeqi Fu <fufuyqqqqqq@gmail.com>
---
 common-user/native/libnative.c | 65 ++++++++++++++++++++++++++++++++++
 include/native/libnative.h     | 11 ++++++
 include/native/native-func.h   | 11 ++++++
 3 files changed, 87 insertions(+)
 create mode 100644 common-user/native/libnative.c
 create mode 100644 include/native/libnative.h
 create mode 100644 include/native/native-func.h

diff --git a/common-user/native/libnative.c b/common-user/native/libnative.c
new file mode 100644
index 0000000000..d40e43c6fe
--- /dev/null
+++ b/common-user/native/libnative.c
@@ -0,0 +1,65 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "native/libnative.h"
+#include "native/native-func.h"
+
+#define STR_MACRO(str) #str
+#define STR(num) STR_MACRO(num)
+
+#if defined(TARGET_I386) || defined(TARGET_X86_64)
+
+/* unused opcode */
+#define __PREFIX_INSTR \
+    ".byte 0x0f,0xff;"
+
+#define NATIVE_CALL_EXPR(func) \
+    __PREFIX_INSTR             \
+    ".word " STR(func) ";" : ::
+#endif
+
+#if defined(TARGET_ARM) || defined(TARGET_AARCH64)
+
+/* unused syscall number */
+#define __PREFIX_INSTR \
+    "svc 0xff;"
+
+#define NATIVE_CALL_EXPR(func) \
+    __PREFIX_INSTR             \
+    ".word " STR(func) ";" : ::
+
+#endif
+
+#if defined(TARGET_MIPS) || defined(TARGET_MIPS64)
+
+/* unused bytes in syscall instructions */
+#define NATIVE_CALL_EXPR(func) \
+    ".long " STR((0x1 << 24) + (func << 8) + 0xC) ";" : ::
+
+#endif
+
+void *memcpy(void *dest, const void *src, size_t n)
+{
+    __asm__ volatile(NATIVE_CALL_EXPR(NATIVE_MEMCPY));
+}
+
+int memcmp(const void *s1, const void *s2, size_t n)
+{
+    __asm__ volatile(NATIVE_CALL_EXPR(NATIVE_MEMCMP));
+}
+void *memset(void *s, int c, size_t n)
+{
+    __asm__ volatile(NATIVE_CALL_EXPR(NATIVE_MEMSET));
+}
+char *strcpy(char *dest, const char *src)
+{
+    __asm__ volatile(NATIVE_CALL_EXPR(NATIVE_STRCPY));
+}
+int strcmp(const char *s1, const char *s2)
+{
+    __asm__ volatile(NATIVE_CALL_EXPR(NATIVE_STRCMP));
+}
+char *strcat(char *dest, const char *src)
+{
+    __asm__ volatile(NATIVE_CALL_EXPR(NATIVE_STRCAT));
+}
diff --git a/include/native/libnative.h b/include/native/libnative.h
new file mode 100644
index 0000000000..d3c24f89f4
--- /dev/null
+++ b/include/native/libnative.h
@@ -0,0 +1,11 @@
+#ifndef __LIBNATIVE_H__
+#define __LIBNATIVE_H__
+
+void *memcpy(void *dest, const void *src, size_t n);
+int memcmp(const void *s1, const void *s2, size_t n);
+void *memset(void *s, int c, size_t n);
+char *strcpy(char *dest, const char *src);
+int strcmp(const char *s1, const char *s2);
+char *strcat(char *dest, const char *src);
+
+#endif /* __LIBNATIVE_H__ */
diff --git a/include/native/native-func.h b/include/native/native-func.h
new file mode 100644
index 0000000000..d48a8e547a
--- /dev/null
+++ b/include/native/native-func.h
@@ -0,0 +1,11 @@
+#ifndef __NATIVE_FUNC_H__
+#define __NATIVE_FUNC_H__
+
+#define NATIVE_MEMCPY 0x1001
+#define NATIVE_MEMCMP 0x1002
+#define NATIVE_MEMSET 0x1003
+#define NATIVE_STRCPY 0x1004
+#define NATIVE_STRCMP 0x1005
+#define NATIVE_STRCAT 0x1006
+
+#endif
-- 
2.34.1